Related papers: Rare B -> K^* (nu) bar(nu) decay beyond standard m…
We investigate the rare baryonic exclusive decays of $\Lambda_b\to \Lambda l^+ l^- (l=e,\mu,\tau)$ with polarized $\Lambda $. Under the approximation of the heavy quark effective theory (HQET), in the standard model we derive the…
We recently measured the branching fraction of the $B^{+}\rightarrow K^{+}\nu\bar{\nu}$ decay using 362fb$^{-1}$ of on-resonance $e^+e^-$ collision data under the assumption of Standard Model kinematics, providing the first evidence for…
We present a search for the rare decays B+ -> K+ nu nubar and B0 -> K0 nu nubar using 459 million BBbar pairs collected with the BaBar detector at the SLAC National Accelerator Laboratory. Flavor-changing neutral-current decays such as…
Soon the NA62 experiment will start looking for the rare K+ ---> pi+ nu nu bar decay. In this talk, its theoretical interests, together with those of the neutral rare decays KL ---> pi0 nu nu bar, KL ---> pi0 e+ e-, and KL ---> pi0 mu+ mu-,…
We examine the exclusive rare decays of $B \to K_{0}^*(1430)\ell\bar{\ell} $ with $K_{0}^*(1430)$ being the p-wave scalar meson and $\ell=\nu,e,\mu,\tau$ in the standard model. The form factors for the $B\to K_{0}^{*}$ transition matrix…
Exclusive weak radiative B meson decays are studied using the covariant oscillator quark model. The branching ratios for the processes B0 to K*0 gamma and B to K* gamma have been estimated. These are in reasonable agreement with the…
We study the branching ratios of rare K and B decays in models with minimal flavour violation, using the presently available information from the universal unitarity triangle analysis and from the measurements of Br(B -> X_s gamma), Br(B ->…
We report the first observation of the exclusive decays \bar B\to D^{(*)}K^{*-}, using 9.66 x 10^{6} B\bar{B} pairs collected at the \Upsilon(4S) with the CLEO detector. We measure the following branching fractions: {\cal B}(B^- -> D^0…
We present the model independent analysis of $\Lambda$ baryon polarizations in the (Lambda_b -> Lambda l^+ l^-) decay. The sensitivity of the averaged 'Lambda' polarizations to the new Wilson coefficients is studied. It is observed that…
We reanalyze the rare decays K^+ -> pi^+ nu nu-bar and K_L -> pi^0 nu nu-bar in a general MSSM with conserved R-parity. Working in the mass eigenstate basis and performing adaptive scanning of a large space of supersymmetric parameters, 16…
We report recent results in rare B decays. Our focus will be on b -> d gamma and b -> s l^+ l^- transitions. We discuss their impact on the CKM phenomenology and their role within our search for new physics. In particular, we analyse the…
Recent experimental results on exclusive semi-tauonic B meson decays, B -> D(*) tau nu, showing sizable deviations from the standard model prediction, suggest a new physics in which the structure of the relevant weak charged interaction may…
The exclusive rare radiative B meson decays to orbitally excited axial-vector mesons K_1^*(1270), K_1(1400) and to the tensor meson K_2^*(1430) are investigated in the framework of the relativistic quark model based on the quasipotential…
We study the branching fractions and the lepton polarization asymmetries of rare $B \to X_s \tau^+ \tau^-$ and $B \to K^{(*)} \tau^+ \tau^-$ modes within the Standard Model and in the Appelquist-Cheng-Dobrescu model, which is a New Physics…
New BABAR measurements are presented for the exclusive rare decays B -> K(*) l+ l- including branching fractions, isospin asymmetries, direct CP violation, and lepton flavor universality for dilepton masses below and above the J/psi…
New preliminary BaBar results for rare leptonic decays $B^- \to K^-\nu \bar{\nu}$ and $B^0\to \ell^+\ell^-$ are reported. Using data collected at the $\FourS$ with the BaBar detector, no evidence for a signal was found yielding the…
The persistent tensions between inclusive and exclusive determinations of $|V_{cb}|$ and $|V_{ub}|$ weaken the power of theoretically clean rare $K$ and $B$ decays in the search for new physics (NP). We demonstrate how this uncertainty can…
We present a new measurement of the purely leptonic decay B- -> tau- nu_tau-bar with a semileptonic B tagging method, using a data sample containing 657*10^6 BB-bar pairs collected with the Belle detector at the KEKB asymmetric e+e-…
In this paper we study the angular distribution of the rare B decay $B \to K^*_2 (\to K \pi) l^+ l^-$, which is expected to be observed soon. We use the standard effective Hamiltonian approach, and use the form factors that have already…
Besides being important to determine Standard Model parameters such as the CKM matrix elements $|V_{cb}|$ and $|V_{ub}|$, semileptonic $B$ decays seem also promising to reveal new physics (NP) phenomena, in particular in connection with the…